This invention relates to the twine wrapping mechanism commonly found in a crop roll forming machine and, more particularly, to apparatus for independently operating a plurality of cutting knives to sever the binding material placed about the periphery of a completed crop roll by the twine wrapping apparatus.
Recently the practice of harvesting crop materials, such as hay, alfalfa, or corn stover, by forming such crop materials into large cylindrically shaped rolls using large roll forming machines has become increasingly popular and economically advantageous in the agricultural industry. The formation of crop materials into large compact cylindrical rolls, rather than rectangular bales as formerly done, permitted the crop material to be deposited in roll form and left in fields for extended periods of time since the rolled material tended to provide a self-shedding protective covering from inclement weather. The ability to leave these rolled bales in fields thus obviated the formerly required additional steps of gathering the rectangular bales and transporting them to a storage area protected from the elements.
The forming of crop material into compact rolls itself is not new. The origins can be traced back 30 or 40 years to the small cylindrical bale of hay or other fiberous material produced by the type of machine illustrated in U.S. Pat. No. 2,336,491, dated Dec. 14, 1943. The rolls of crop material produced by this type of machine, in the context of the economic factors of the current agricultural marketplace, suffered from the principal disadvantage of producing rolls of such small diameter that excessive spoilage occurred around the periphery of the roll in comparison to the overall diameter of the roll due to weathering when such rolls were stored in the field.
A later type of machine produced generally cylindrically shaped rolls of crop material by rolling the material along the ground until a roll of desired size was obtained. Crop rolls of this type, produced by machines of the type disclosed in prior U.S. Pat. No. 3,110,145, dated Nov. 12, 1963, suffered several inherent disadvantages because of the technique that was used to form them. This technique permitted an undesirable amount of crop material to be left upon the ground without being included in the crop roll. Additionally, dirt, clods of earth, stones and the like were picked up by the roll and included therein.
The latest and most successful type of machine forming crop rolls utilized a method which picked up a swath or windrow of crop material from the field and deposited it onto a lower conveyor. The conveyor then transported the material to a roll forming region where an apron or flight of belts, usually positioned above and adjacent the conveyor, moved in a suitable direction to rotate the crop material and form a large, compact cylindrical bale. Variations of the type of machine utilizing this principle are illustrated in U.S. Pat. No. 3,859,909 to Mast dated Jan. 14, 1975, and U.S. Pat. No. 3,722,197 dated Mar. 27, 1973.
All of the above-cited crop roll foming machines utilized in some form crop material binding means to wrap the various sized compact crop rolls. The binding material commonly took the form of twine and the binding means, accordingly, became known as twine wrapping means or apparatus. The apparatus was used in a twine wrapping cycle that included the steps of feeding the twine, wrapping the completed roll or bale and severing the twine prior to ejecting the roll or bale from the machine. Generally, the twine wrapping apparatus employed by these machines included an elongated tube which oscillated in a predetermined path across the bale forming region to dispense the binding material as the material was wrapped about the bale. Automatic twine wrapping apparatus that serially undertook the previously mentioned three steps without any operator involvement, hydraulically or electrically powered apparatus requirng manual activation, and completely manually operated twine wrapping apparatus have been used in the art on the varying machines used to form cylindrical rolls of crop material. Operators and manufacturers of the more recent large roll forming machines quickly realized that the less time required for the twine wrapping cycle, the more time there would be for gathering crop material from the field to form completed crop rolls.
The current increasing popularity of large crop roll forming machines has seen their use broaden from merely rolling wintering forage for livestock to rolling high protein crops. Therefore, these machines have been the focal point of many ideas for developing twine wrapping apparatus that will appreciably decrease the amount of time required for the twine wrapping cycle, as well as active operator involvement in the cycle. Regardless of whether the twine wrapping apparatus is manual, powered or automatic, the time required to complete the cycle is directly a function of the amount of time it takes to dispense the binding material about the periphery of the completed crop roll and then cut the material. When only a single elongated tube is used to oscillate across the bale forming region to dispense binding material, the time required will necessarily be longer than if multiple elongated dispensing tubes are used to bind the full length of a completed crop roll. Accordingly, the use of multiple elongated dispensing tubes that oscillate simultaneously across distinct portions of the entire length of a completed crop roll substantially decrease the length of time required for the twine wrapping cycle to be completed. However, the use of multiple dispensing tubes requires the use of multiple binding material severing means.
The severing means must be synchronized in operation so that the strands of binding material dispensed from the elongated dispensing tubes are severed at approximately the same instant in time so that the twine wrapping cycle may be promptly terminated and the completed crop roll ejected from the crop roll forming machine. The multiple severing means also have to be reliable so that each and every strand of binding material is completely severed before the completed crop roll is ejected from the machine. Since cutting blades are commonly employed as the severing means, wear naturally occurs along the cutting edges. Extended use of the roll forming machine can result in sufficient wear occurring to one or more of the cutting blades so that one or more of the blades, usually operated by a unitary control system, will not cut one or more of the strands of binding material. Even after sharpening, the unitarily controlled and operated cutting blades require frequent adjustments to ensure they operate in a synchronized manner that will cut all the strands of twine at substantially the same time. Early efforts to utilize multiple cutting blades often resulted in only a portion of the multiple cutting blades effectively cutting the binding material. When this occurred, valuable time was wasted by the operator of a roll forming machine using automatic twine wrapping apparatus by having to manually sever the uncut pieces of binding material.
The foregoing problems are solved in the design of the apparatus comprising the present invention by providing multiple severing means in the form of cutting blades that are independently operable to concurrently sever binding material dispensed from a plurality of elongated dispensing tubes in a crop roll forming machine.